Product details
| Grade | Loctite 542 |
| Strength | Medium strength |
| Colour | Brown |
| Family | Thread sealants |
| Brand | Loctite (Henkel) |
| Stock | Held in Dubai — buy one or bulk |
Pack sizes
Prices on request. Tell us the quantity you need.
Check stockWhat Loctite 542 is for
The fine-thread sealant. At 400–800 mPa·s it is thin enough to travel into the close threads of hydraulic and pneumatic fittings, where a paste-grade sealant would sit on the surface and be scraped off on assembly. It seals and locks against shock and vibration, and holds full strength in motor oil at 125°C out to 1,000 hours.
Key features
- Low viscosity — penetrates fine threads on hydraulic and pneumatic fittings
- Medium strength — 15 N·m breakaway on M10, 25 N·m breakloose
- ≥6.5 N/mm² compressive shear
- 100% of initial strength retained in motor oil at 125°C after 1,000 hours
- Seals instantly to moderate pressure once properly tightened
- Hand-tool removable on normal fitting sizes
Typical applications
- Hydraulic fittings
- Fine pipe threads
Technical data
Uncured material
| Technology | Acrylic |
| Chemical type | Dimethacrylate ester |
| Appearance | Brown liquid |
| Components | One component — no mixing |
| Cure | Anaerobic; secondary cure by activator |
| Viscosity, Brookfield RVT 25°C | Spindle 2 at 20 rpm: 400–800 mPa·s |
| Viscosity at 2.5 rpm | 1,200–2,750 mPa·s |
| Viscosity, EN 12092 MV 25°C | 150 mPa·s at 277 s⁻¹ |
| Specific gravity at 25°C | 1.06 |
Torque and strength
After 24 hours at 22°C.
| Breakaway torque, M10 steel | 15 N·m (130 lb·in) |
| Prevail torque, M10 steel | 9 N·m (80 lb·in) |
| Breakloose torque, pre-torqued to 5 N·m | 25 N·m (220 lb·in) |
| Max. prevail torque, pre-torqued to 5 N·m | 25 N·m (220 lb·in) |
| Compressive shear strength (ISO 10123) | ≥6.5 N/mm² (940 psi) |
Chemical resistance
As a percentage of initial strength after ageing.
| Environment | °C | 100 h | 500 h | 1,000 h |
|---|
| Motor oil (MIL-L-46152) | 125 | 100% | 100% | 100% |
| Unleaded petrol | 22 | 100% | 100% | 95% |
| Brake fluid | 22 | 100% | 100% | 95% |
| Ethanol | 22 | 100% | 100% | 95% |
| Water / glycol 50:50 | 87 | 90% | 90% | 90% |
| Acetone | 22 | 100% | 80% | 80% |
Cured material
| Coefficient of thermal expansion (ISO 11359-2) | 80 × 10⁻⁶ K⁻¹ |
| Thermal conductivity (ISO 8302) | 0.1 W/(m·K) |
| Specific heat | 0.3 kJ/(kg·K) |
How to use it
- Clean all surfaces, external and internal, with a Loctite cleaning solvent and allow to dry.
- On inactive metals, or if the cure is too slow, spray with Loctite SF 7471 or SF 7649 activator and allow to dry.
- Apply a 360° bead to the leading threads of the male fitting, leaving the first thread free.
- Force the material into the thread roots to fill the voids. On larger threads, apply a 360° bead to the female threads as well.
- Assemble and wrench-tighten in line with the fitting manufacturer's recommendations.
- A properly tightened fitting seals instantly to moderate pressure; allow 24 hours for maximum pressure and solvent resistance.
Handling and storage
- Not recommended for pure oxygen or oxygen-rich systems.
- Not a sealant for chlorine or other strong oxidising materials.
- Not normally recommended on plastics — thermoplastics can stress-crack.
- Disassembly is with standard hand tools; over 1 in. diameter or long engagement may need localised heat to about 250°C.
- Store unopened and dry, ideally 8°C to 21°C; outside 8–28°C the properties can be affected.
- Do not return decanted product to the original container.
Loctite 542 or 577?
Both are medium-strength thread sealants. The difference is thread size. 542 is low viscosity for fine hydraulic and pneumatic threads where a paste would be wiped off. 577 is a thixotropic paste with 0.25 mm gap capability for coarse or worn threads. Fine fittings → 542. Loose or large threads → 577.
Always read the current technical and safety data before use —
ask us and we'll send it with your quotation.
